Art of synchronizing alternating-current generators.



B. P. ROMAIN. ART OF SYNOHRONIZING' ALTERNATING CURRENT GENERATORS.

APPLIOATION FILED DEC. 8, 1909.

1,057,278. Patented M21225, 191s.

. nating-Current Generators, of which the fol-' UNITED STATES PATENT OFFICE- nuncnmn r. Romain, or NE ARK, miw messy, 1155101101; 'i'o wnsrou Emc- TRICAL INSTRUMENT contain. or wavmr ru n, NEW Jmn's iir, A conrom HON or mew JERSEY.

m or srnci momzrne u'rs amitrma-cuanamr Gm'm s I Specification of. Letters intent.

, Application filed December 8, 1900. Serial Io. 532,087.

To all whom, it may concern. 1. I p

Be it known that I, BURCHARD P. Romain, a citizen of the United States, and resident of Newark, county of Essex, and State of. New. Jersey, have made a new and useful'Invention in the Art of Synchronizing Alterlowing is a specification.

My invention relates to a novel niethodof and apparatus for indicating when alternating current generators are in synchronism.

The novel method involved and the eneral principles upon which my new sync ronizing device operates may be clearly under stood. if it be'assumed that the motion of a movable system, which oscillates with a frequency corresponding to the difference in frequency of two alternating current generators can be made visible, in one direction only, during each of its cycles, the ocular effect will be that of a continuously rotating object seen during only a portion of each revolution, and having an average angular velocity equal to the difference in the frequencies of the two machines. If this motion of the movable body is made visible in one direction when the first machine has a higher frequency than the second, and in the other direction when the second machine has a higher frequency than the first, it will at once be seen whether the incomin machine is running too fast or too slow. uch a device would obviously perfectly serve the purpose of correctly indicating when the frequency of the two machines was equal, but would not indicate when the phase relationship of the two machines was ri ht for cou-. pling together. If, now, such a ifierence in frequency indicating instrument can be combined with a device which will serve to correctly indicate the phase coincidence of the two machines, the whole combination be comes an accurate synchroscope or synchronizing device. Such, in eneral terms, is'the basic principle upon w ich my invention rests and the method and-means I prefer to employ in carryingmy invention into practice will be more fully understood from what. follows. v v

For a full and clear understanding of my invention, such as will enable others skilled in the art to construct and use the same, reference is had to the accompanying drawings,- in which,

' Figure 1 is a diagrammatic view illustrat ing two alternating current generators, one of which is connected directly in circuit with a system .of current supply and with my 3 novel apparatus, andthe other also in circuit with my apparatus but out of circuit with the system of current supply. Fig. 2 jis a diagrammatic view illustrating the theo-' retical mpde of operation.

Referrin to the drawings in detail, W, W represent t e mains of a source of current supply and A an alternating current generator supposed to be running and operatively connected thereto through a switch S w. B

represents azsecond alternating current generator provided with a switch S 'w for connecting it directly to the same mains when it is found to be in synchronism with the first generator.

novel synchroscope'utilizes an electr'oynamometer, preferably of the well known Weston type, such as is described in Reissue Patent No. 11,250, granted to Edward Weston on the 28th day of J une," 1892, and having static-nary field coils F, F'ope'ratively connected by conductors w, 20' directly tothe mains W, W, B being a non-inductive resistance for regulating the current flow thereto.

' M represents the movable coil of fthe instrument which carries an index needle E provided with a pointer P, said movable coil havin two spirally disposed conducting re- Patented Mar. 25, 1913. p

tracti e springs which are opposed to each other and normally hold the coil in the central position shown, when no'current is fiow-, 'ing, and connected directly in circu t with conductors 'w w running directly to conductors which connect the the switch 8 w. I

T represents a transformer, the primary coilsrP P of which are connected by j co'n ductors directly to conductors w, w and w generator with nected by conductors w w to an incandescent electric lamp L located directly below the translucent face D of the instrument,

the arrangement being such that the'lamp L will be lighted to its maximum lirilliaiicy' when the machines A and B arein phase, and that the pointer P of the vibratory nee- 'v 1"the coils of the secondaryS being condle E may pass as it oscillates, between the 60 the shaded area, and lighted approximately while V moves across the clear area. When.

dicated as shown upon such face in enlarged letters. Thistranslucent face is made preferably of ground glass and by reason of this fact theindex needle E and pointer P are only visible, when the lamp L is glowing.

C represents a condenser located in series \vlth the movable C011 M of the system and r represents asmall non-inductive resistance for giving to the current flowing through,

the movable-coil a phase angle of 90 ahead of that in the field coil circuit when the E. M. Fs. impressed across the movable and field co-il circuits have the same phase and frequency. This small nonf-inductive resistance'is only used when this .'angle is.

enough greater than 90 to cause a visible error.

It will be evident that when the two machines A and B are in phase no torque will beexerted upon the movable coil M and the pointer P will-stand in its normal or central position,- under the influence of the spiral ent upon which one is leading in phase.

When the machines are in phase opposition the pointer P. will, of course, stand in the central or normal \position, but the lamp,

. under this condition, will be absolutely nonluminous and, therefore, the pointer cannot be seen.

Referring now to let V represent the instantaneous voltage of the generator A and the current through the field coils of I the instrument; let V represent the instantaneo-us voltage of B and I the instantaneous current through the movable coil M. We nowhave only to deal with the phase relations of A and B; hence we may for simplicity consider V to be stationary, while V revolves with the frequency equal to the difference in the frequencies of the machines A and B, and in one direction or the other according to which is the greater. The lamp .L is so connected that if V and V are equal the E. M. F. across it will be zero when V is at D and will be a maximum When'V is at L. Since the E. M. F. across the lamp L is proportional to the resultant of V and V this E. M. 'F. gradually increases as V moves in either direction from D to L The instrument is so constructed that the E. M. F. acrossthe lamp, when V is at M or N, is. approximately such that any higher value causes the lamp to glow visibly. Under these conditions the lamp will be dark substantially while V moves across V is at N, V and I will be in phase and the pointer will be at one or the other of. the extreme ends of its travel, dependent upon the connections of the movable coil M to the conductors w 10 If V travels in the direction shownby the arrow in Fig.

2 the pointer will ,move under the t-ranslucent.face D (Fig. 1) from right to left reaching the central or normal position when V and V are in phase, and then V will continue to travel to M (Fig. 2). about this point the lamp is extinguished and remains so until V is advanced approximately to- N when the pointer I is again at the extreme right of the translucent faceand is ready for a similar cycle. If V moves in the opposite direction the pointer P could only be seen moving in the reverse direction.

may travel ,the full, length of the translucent face on volt-ages or frequencies varying from. the normal by ,an amount likely to be found in practice,'tlie instrument is so adjusted that this pointer can-move over the full length thereof with the lowest voltage and frequency with which it will be called uponto operate. Further travel under other conditions is either arrested by cushioned springs located at the opposite ,ends of the throw of the needle in the well known manner, or is obscured from view under the cap or cover of the instrument.

I do not limit myself in the practice of my method to the synchroscope embracing the especial details of construction illustrated in the accompanying drawings,.as obviously a number of the features thereof might be departed from and still come within the scope of my claims hereinafter made. To illustrate, the condenser C may be replaced by a reactive coil and either of these may be placed, if preferred, in the field circuit; or the electro-dynamometer may be replaced by a statically actuated instrument or equivalent electromotive device. Two individual transformers may also replace the single transformer shown, these matters being well within the skill of those versed in the art. The movable and fixed coil circuits may be arranged and interconnected in other ways which will readily suggest themselves to such persons and the light from the lamp L, or from any luminous source variously controlled may be utilized in known ways and still come within the scope of my invention which is directed broadly to the combined use of an electro-dynamometer or motive device, and an electric or other lamp for indicating the phase relations of two alternating current generators and in such manner that when the movable part oflthe electromotive device is substantially stationary and the lamp at full glow two-machines connected in circuit therewith are necessarily running in synchronis m and phase coincidence, and may be switched into circuit with each other.

Itwill be observed that since the lamp L.

Atl

In, order thatthe pointer is in circuit with both altern'ators A and. B, the li ht emitted from said lamp and reflectetf from said pointer P will be at its maximum when the currents of said alternators are in, or nearly in, phase. It will further be seen, asabovei stated, that said lamp will go out when the said" currents are in opposition'so that the pointer P cannot then be seen. Likewise, it will be clear that the ap arent rotations of-the pointer P in each irection will have speeds inversely proportional to the. change of base difference between the currents, whic speeds will be zero when the currents are of the same frequency, whether substantiall in phase or in opposition. It, therefore, fo lows that by combining the transformer T, lamp L and pointer P in the relations disclosed, the a paratus indicates at all times whether t e currents are approaching the same phase or approaching opposition, and are in base,

or are in opposition, 'a'result not attainable with instruments heretofore proposed, so faras I am aware.

g Having thus described my invention what ent of the United States is .1. The method of ascertaining when cur rents from two alternatingv current generators having different frequencies are in phase, which consists in causing the differences in frequency o f'the two currents to move an ob'ect; and util'izing the difference in phase 0% saidjcurrentsto soilluminate the said object as to produce the appearance I claim and desire to secure by'Letters Patof a rotation in one directionwhen the first second and to pr machine has a hi her fre'quency than the rotation in the opposite direction when the second machine has a higher frequency than the first, substantially as described.

a 2. The method of -ascertaining when Clll rents from two, alternating generators are.

in phase inorder to readily ad ust the speeds of said generators preparatory, tot'connecting the same .inparallel, whichconsists in causing the difieren'ces in phase ofthe said currents toproduce successive di-fierences in the brilliancy ofa light; causing the. differ-.

ences in frequencies of. said currents to move an ob ect; simultaneously illuminating said.

' moving object from' said. -light so as to cause rents from't'wo alternating the, latterf'toapparently rotate in a definite,

row brighter as the currents ap roach the directiondependent. 1 upon which generator is running 'e" faster and ffinal'lg to cause said changes-in brillian'cy and sai eneratoriclosely approximates the speed of t 'e othensubstantlally as described.

3. The method of ascertaining when cur- I generators are in phase" or are in opposition while adjusting the speed of one of said generators be: fore connecting them in-parallel, which consists in causing the relative changes in the ace the appearance of a;

apparent rotations w cease as the speedof the one" the higher speed; and as the speed of the "machines approach each other causing said "therewith in. accordance with the difference ment in one direction or-another according 'syn'chronism,.- is attain tively successive movements of an object and changes in the light emitted from a lamp; causing said ob ect to be so illuminated from said lam as to produce apparent rotations of sai object in different directions according to which generator has apparent rotations to slow down and the said light to increase until said speeds are approximately equal 'when said apparent rotations cease and said light is constant, substantially as described.

4. The method of ascertaining when two alternating current generators have the proper speeds to be connected in parallel, which consists in causing the frequency dif-l ference" of the currents to move an object rate ofchange of the phase difierence of the currents; causingthe phase diflerence to vary the intensity of a light; said object being so illuminated by said varying light as to produce apparent rotations ofs'aid ob- -ject in diflerent directions according to which generator is running" the faster and to cause said apparent rotations radually to slow down and cease when saif currents 5 approach-the'same frequency, whether they areapproa'chin the same phase, or opposi-' t-ion, substantia ly as described.

5: A synchroscope, comprising an electromotive device --pr0vided with a stationary and, a movable part adapted'to be opera; tively connected 'in'circu t withv a pair of alternating current generators; an electric lamp; connections between each generator and said lamp adapted to cause the light 5 emitted to vary with the difference in phase of said generators; the movable part of the .said 'electro-motive device being 'provided' with an indicating object adapted to move in fre uenc of said generators; said-mov ing in icatmg object being' soilluminated by-said varying light as to cause-said object to apparently rotate for a part of its moveto= which machine .is running the faster; and theconnections 'being such that the luminous efiects of the lamp continually same phase until finall' when e proper no the indicating ob ject isstationary and the luminous efiect of thela'nip' thereon is constant, substantially as described.- r

'6. synchroscope for indicating the phase relations'of two alternate current generator's comprising a movable indicator; an electr c lam v illuminatin said indicator; COIlIIGCtlQIlS' tween each circuit of each g'enerator ands'aid lamp whereby the phase difas at a speed depending upon the instantaneous ferences of said currents vary the said illuminating effect of said lamp; additional connections between the circuits of said generators and said indicator for operating the latter by the differences in frequency of said currents; said connections being such that when synchronism is approached the lamp will glow at its maximum brilliancy and the indicator will be stationary, and when the currents are in opposition the said lamp 1 will be extinguished while the indicator will also be stationary, substantially as described.

,7. A s'ynchroscope for indicating thef phase relations of two alternate current generators comprising a movable indicator; an

electric lamp illuminating said indicator; connections between each circuit of each generator and said lamp whereby the phase differences ofsaid currents vary the said illuminating eifect of the lamp; additional connections between the circuits of said generators and said indicator for operating the latter by the difl'erences in frequency of said currents, said connections being such that when synchronism is approached the lamp will glow at its maximum brilliancy and the indicator will be stationary, and

circuit with 'two alternating current genera torsto be synchronized; an indicator adapted to, move with the movable part of said electro-dynamometer'; a lamp adapted to illuminate said indicator and so connected with both generators as to glow at its maximum brilllancy when synchronism is attained, but to glow with a less and less brilliancy asthe said'currents approach opposition; and means for concealing-the indicator from View when the currents are not in phase, substantially as described.

9. Means for ascertaining when two alternating current generators are in proper running relation preparatory to connecting them,in parallel, comprising an electromotive device having a stationary and a movable part foronnection to said generators and an indicator carried by the movable part in combination with an electric lamp and connections with both generators adapted to i so illuminatesaid indicator as to cause it to have apparent rotations; said connec-. tions causing the lamp to glow at its maximum brilliancy when the generators have been so adjusted as to be in the same phase; and means for concealing the indicator from view when the currents are not in the same phase, substantially as described.

10. In a synchroscope for ascertaining when two alternating current generators are in proper running relation, the combination of a movable indicator; electricallycontrolled means for causing the same to vibrate back and forth with' a speed proportional tothe differences in frequency of said generators with which said indicator is connected; an electric lamp operatively connected with each generator adapted to illuminate said indicator during half vi rations only, and thereby produce apparent rotations of said indicator; and said connections being such that said lamp will glow at its maximum brilliancy only, when proper synchronism is attained, and will become extinguished when opposition is bad, substantially as described.

11'. In a synchroscope, the combination of a movable indicator; a dynamometer with which said indicator is operatively connected; two alternating current generators; circuits between said generators and said dynamometer; an electric lamp' adapted to illuminate said indicator; inductive connections between saidlamp and each of said generators, the connections being such that the brilliancy of said lamp will vary according to the phase relation of said generators and will become a maximum when said generators are in phase; and means for concealing the indicator when the lamp is not glowing, substantially as described.

12. In a synchroscope adapted to indicate whether two alternating current generators are in phase or in opposition, the combination of means adapted to be fed from each of 'said generators for causing a lamp to be lighted when the currents are in phase, to be dimmed when not in phase, and to be extinguished when in opposition; with means also operated from each of said generators for causing a pointer illuminated from said lamp to have apparent movements in definite directions at decreasing speeds as said currents approach the same frequency, and to be stationary when such frequency has been attained, substantially as described. I

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

BURCHARD P. ROMAIN.

.Wit-nesses:

J. A. DORRIAN, CAx'roN BROWN. 

